共查询到20条相似文献,搜索用时 15 毫秒
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板料成形中,压边力是控制板料流动的重要因素。前人大量的研究表明,在拉伸成形的不同行程施加合适的变压边力(VBHF),可有效避免板料成形中起皱和破裂的缺陷。文章基于压边力成形窗口的定义和分析,提出新的控制目标,并采用PID闭环控制策略来优化不同冲压行程中分块压边圈上的压边力。针对一个具有不同角部半径的盒型件进行了闭环的变压边力优化模拟,得到其不同位置的分块压边圈随行程变化的最优压边力曲线,并在变压边力压机上进行实验验证,结果表明,使用铝合金板料并在恒定压边力下难以成形的盒形件,在最优变压边力下成功成形。 相似文献
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本文总结了影响板料成形性能的因素并指出相应改善方法 ,重点研究了压边圈形变对板料成形性能的影响 ,并指出考虑BH形变的BHF控制是压边力控制研究的方向。 相似文献
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M.R. Morovvati B. Mollaei-DarianiM.H. Asadian-Ardakani 《Journal of Materials Processing Technology》2010,210(13):1738-1747
In this paper, the wrinkling of two-layer (aluminum-stainless steel) sheets in the deep drawing process, is investigated through an analytical method, numerical simulations, and experiments. In a deep drawing process, wrinkling can always be eliminated with an increase in the blank holder force (BHF). Thus, the aim of this study is to obtain the minimum required BHF to prevent wrinkling. In the analytical model, energy method is used to predict the wrinkling. Also, FE simulations were performed to study the effect of forming parameters on wrinkling. Experiments have been conducted to verify the analytical model and FE simulations. The effects of parameters such as the material properties of aluminum layer and lay-up on BHF and forming force are investigated. Results demonstrate that the optimum BHF is dependent on the blank geometry, material properties and lay-up. It is shown that BHF is greater when aluminum is in contact with the punch. Results show a good agreement between analytical, FE, and experimental results. 相似文献
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压边力是板料拉延成形过程的重要工艺参数之一,合理控制压边力的大小,可避免成形件起皱或破裂等缺陷.建立了三角冲压件的有限元模型,利用DYNAFORM软件,采用数值模拟的方法研究了三角形冲压件拉深时,压边力随时间及位置变化对成形性能的影响.分析结果表明,通过控制拉深过程压边力值的大小和分布,能有效地控制金属的流动,提高板材的成形性能. 相似文献
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以矩盒形件为研究对象,对凸缘部分按几何特征予以分区,并在eta/DYNAFORM 5.6和MSC.Marc/Mentat软件中对其分区压边拉深成形过程进行有限元仿真,分析各区域压边力对零件成形性能的影响,给出了矩盒形件的确定分区压边力大小的原则;结合矩盒形件拉深时的变形特点和材料流动情况,在相关文献研究的基础上,对分区方式进行优化,提出了结合变形特点的分区方式;在YT32-315C四柱液压机和自主研制的分区拉深装置上,对矩盒形件进行分区压边拉深的实验,实验结果和有限元仿真结果基本相符。矩盒形件的分区方式应按几何特征与变形特点划分。 相似文献
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Adaptive FEM simulation for prediction of variable blank holder force in conical cup drawing 总被引:14,自引:0,他引:14
Z. Q. Sheng S. Jirathearanat T. Altan 《International Journal of Machine Tools and Manufacture》2004,44(5):487-494
Fracture and wrinkling are two primary failure modes in deep drawing of sheet metal parts. Previous studies showed that properly selected variable blank holder force (BHF) profile, i.e. variation of BHF with punch stroke, can eliminate these failures to draw deeper parts. In this study, an adaptive simulation strategy was developed to adjust the magnitude of the BHF continuously during the simulation process. Thus, a BHF profile is predicted in a single process simulation run and the computation time is reduced. The proposed strategy has been applied successfully to two conical cup drawing operations. The predictions have been compared with experiments and the results indicate that the adaptive simulation strategy can also be used to improve the drawing process for forming non-symmetric parts. 相似文献
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直壁矩形盒渐进成形技术 总被引:2,自引:1,他引:1
介绍了金属板料数控渐进成形的原理、板料变形过程及直壁矩形盒成形的工艺规划。根据正弦定律,直壁矩形盒采用数控渐进成形工艺不能一次成形。经设计平行线形工具路径方法,并进行试验和分析,得出影响直壁矩形盒成形的主要参数是成形半锥角。 相似文献
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Kyung Seok Oh 《Journal of Materials Processing Technology》2011,211(4):695-707
A new test method including the tool shape and test procedure was developed to evaluate sheet metal formability using the finite element method (FEM). This method is intended to generate the various modes of deformation and to control the onset of failure independently under each mode so that the forming limit diagram (FLD) achieves a good representation of a wide range of strains.A blank holder force-punch stroke diagram with three failure loci is introduced to define the optimum process condition and the formability index by which each material is quantitatively evaluated. The test procedure of this method consists of three steps: drawing a blank holder force (BHF)-punch stroke diagram, measuring strains from the part stamped at the optimum process condition, and grading the test materials using the formability index. In numerical simulations under optimum process conditions, sheet metals can fail due to multi-mode rupture; this failure leads to a widely balanced strain distribution in the FLD such that strains are developed near the forming limit over a wide range of forming modes.Experiments were conducted on three grades of steel sheets to validate the proposed method. Stamping results yield well-defined strain signatures having a wide range of strain distribution in the FLD in all materials tested. The outcomes of the shape and strain behaviors agree well with the numerical results. 相似文献
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将拉延筋模型引入到板料成形动力显式有限元分析中,并以汽车前照灯矩形反光镜为应用实例,对其拉延成形过程进行了模拟。 相似文献
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On the acting pressure in laser deep drawing 总被引:2,自引:1,他引:1
Through the continuing trend of miniaturization new cost efficient and fast methods for processing of small parts are required.
In this paper a non-mechanical process for the forming process of micro deep drawing is presented. This new pulsed laser based
deep drawing process utilizes an initiated plasma shock wave at the target, which forms the sheet. Several pulses can be applied
at one point and therefore high forming degrees can be reached without increasing the energy density. In this article the
pressure of the shock wave is measured and optimized. Furthermore laser deep drawing of samples made out of pure aluminum,
copper and stainless steel sheet metal with thicknesses of 20 and 50 μm are shown. Finally the forming behavior after single
pulses is presented. 相似文献
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